Various designs of transport vehicles for large cylindrical bales, commonly known as “round bales”, have been provided previously. In one arrangement, as disclosed in U.S. Pat. No. 3,942,666 to Pfremmer, a trailer carries two parallel rows of round bales. The bales are engaged by a lifting apparatus at a front end of a trailer and flipped rearwards onto the trailer. The bales land on a single longitudinal conveyor chain and are maintained in a position substantially centered on the conveyor chain by a confining wall on each side. The conveyor chain has lugs extending upward from the chain that extend into the bale and grab the bale to move it rearward with the conveyor chain to accept another bale at the front end. Bales are loaded on the front end and moved successively rearward by the lugs on the conveyor chain until the trailer is filled. The trailer of Pfremmer is difficult to use because the bales have to be positioned in front of the trailer.
Another arrangement, shown in U.S. Pat. No. 4,076,138 to Honomichl, Sr. more conveniently loads bales from the side, which can be more convenient than the above mentioned arrangement, but only allows a single row of bales to be loaded onto a trailer. Similar to the trailer of Pfremmer, the bales land on a single longitudinal conveyor chain and are maintained in a position on the conveyor chain by a cradle comprising a raised rail on each side. The conveyor chain carries hooks or pins, similar to the lugs of Pfremmer extending outwardly to engage the bales so they will slide on the rails with the conveyor chain.
Some examples of arrangements having three rows of bales are shown in U.S. Pat. No. 5,180,271 to Farden, and U.S. Pat. No. 5,320,477 to Druse, Sr. These arrangements do not have a convenient loading arrangement on the trailer. The bales are simply loaded onto the trailer by a tractor or the like which has to drive beside the trailer loading the bales thereon. The arrangements may not be convenient in that the bales have to be precisely positioned onto the trailer in order for the trailer to properly carry the bales.
The lugs, hooks, pins, or the like on the conveyor chains used in the above arrangements of Pfremmer and Honomichl, Sr. can damage the strings tying the bale when the bale is dropped on the conveyor chain during loading, and also puncture the covering on plastic wrapped bales. Also the protruding devices can rip the strings tying the bale if the conveyor chain is not stopped when the bales are obstructed as sometimes happens. For these reasons it is common to use a pair of conveyor chains moving in unison under each row of bales. The side-by side conveyors act as the cradle, maintaining the bales in position, with only a parallel safety rail running adjacent to prevent the bale from jumping off the conveyor chains during transport. With two conveyor chains, it is not necessary to engage the bales with hooks or lugs, as the bales are resting on the conveyor chains and so move when it moves. The load engaging faces of these conveyor chains comprise metal that does not provide appreciable friction between the face and the bale.
Such a bale trailer is illustrated in the laid open Canadian Patent application 2,300,006 of Rempel.
The difference in the two types of conveyor chains is evident when unloading the bales. Typically it is desired to store the bales on the ground pushed tightly together end-to-end. To accomplish this, the new load of bales is positioned with the load bed tilted and the rear end near the ground such that a row of bales on the trailer is in end-to-end alignment with the bales on the ground. The conveyor chain is operated to carry the bales rearward and off the trailer as the trailer moves ahead. Where the conveyor chain includes hooks, considerable force can be exerted to push the bales together, however if the speed of the trailer forward is not synchronized with the speed of the conveyor chain rearward problems occur. If too fast, the bales are not pushed together, while if too slow, the hooks on the conveyor chain move rearward through the strings and bale, causing damage, since the bales are essentially obstructed relative to the conveyor chain. Where possible on level ground in good conditions, the tow vehicle is simply put in neutral and the conveyor chain is operated to push the bales off and at the same time, as the bales push together the trailer is pushed forward, effectively synchronizing the speeds.
With a double conveyor chain with no hooks, there is very little friction and the conveyor chain simply slides under the bales if there is any resistance. Such an apparatus is unable to push the bales closely together for storage.
Conveyor chains are expensive and require maintenance and adjustment. It would be an advantage to provide a bale trailer with only one conveyor chain for each row of bales, as in Pfremmer and Honomichl, Sr. wherein the conveyor chain was configured to reduce damage to the bales, and yet could provide some force to push the bales together for storage on the ground.